Gender, gait and knee OA: Kinematic data have rehab implications

In the moment: Rehabilitation..

Women with and without knee osteo­arthritis (OA) demonstrate greater knee abduction and hip adduction during gait than their male counterparts, according to research from Canada that supports the concept of gender-specific rehabilitation in this population.

Gender should be taken into account when studying the biomechanical etiology of knee OA, and the development of gender-specific analysis and rehabilitation protocols are necessary, the authors wrote.

“I believe this study provides very strong evidence that rehabilitation programs and [prevention] strategies need to be subgroup-specific,” said study author Reed Ferber PhD ATC, an associate professor in the faculties of kinesiology and nursing at the University of Calgary in Alberta.

The study included 100 participants with knee OA (55 women), aged 33 to 72 years, and 43 healthy individuals (25 women), aged 40 to 79 years. The OA group had a 100-mm knee pain visual analog scale (VAS) above 20 mm on most days of the week preceding enrollment and a Kellgren-Lawrence (KL) grade less than three, indicating mild to moderate radiographic OA. The researchers assessed 112 kinematic variables as the participants walked on a treadmill at self-selected speeds ranging from 1 m/s to 1.3 m/s.

Women with knee OA had greater knee abduction at touchdown and during swing, and a greater maximum peak hip adduction angle during stance, compared with men with knee OA; similar differences were also seen between women and men without knee OA. However, no differences in the discrete variables were evident between healthy men and men with knee OA or between healthy women and women with knee OA. The data were epublished in April by the online journal BMC Musculo­skeletal Disorders.

“Our classification method shows a maximum classification accuracy of eighty-three percent between OA male and OA female patients. So, a small proportion of males have gait kinematic patterns similar to females and vice versa,” Ferber said.

Previous assessments of gender-specific gait patterns in patients with knee OA have been inconsistent, perhaps in part because a number of characteristics of knee OA—including pain—can affect gait in ways that may obscure other associations; the inclusion criteria in the current study were designed to address some of these issues, he said.

“Certainly, it is well known that higher pain values can influence gait kinematics, and most previous studies have used a mixed cohort of knee OA patients with mild to moderate and severe pain and symptoms,” Ferber said. “We tried to investigate a homogeneous cohort so that the influence of pain would be minimized.”

Although many knee OA interventions are designed to address frontal plane kinetics rather than kinematics, Ferber said the gender differences observed in the current study may not extend to kinetic variables. A systematic review and meta-analysis the Calgary group completed in 2013 did not find consistent evidence that external knee adduction moment differs between those with and without knee OA or between disease severity levels.

“In fact, we found that only temporospatial and kinematic gait alterations associated with knee OA increased in magnitude with increasing disease severity,” he said.

“In general, I think our present state of knowledge is that sex differences should be accounted for in OA gait studies (and indeed in studies involving imaging, biomarkers, strength, etc). We are beginning to uncover different pathomechanical processes for men and women, which, once are established, will help with person-specific interventions,” Hubley-Kozey wrote in an email to LER.